A U.S. judge has ruled AMR Corp’s American Airlines and United Continental Holdings, Inc. must face trial over claims of negligence relating to the September 11 attacks on New York’s World Trade Center in 2001.

Almost eleven years ago, 19 terrorists from the Islamist militant group al-Qaeda hijacked four passenger jets, including American Airlines Flight 11 and United Airlines Flight 175, which were intentionally crashed into New York’s Twin Towers, American Airlines Flight 77, which was flown into the Pentagon and United Airlines Flight 93, which was meant to crash into the United States Capitol Building in Washington, D.C., but was unsuccessful. Almost 3,000 people were killed.

According to NBC News, in July 2001 World Trade Center Properties, LLC (WTCP) purchased 99-year leases to four World Trade Center buildings from the Port Authority of New York and New Jersey, Inc. for $2.805 billion. In a lawsuit against United Airlines and American Airlines, WTCP is claiming, “the terrorists could not have boarded and hijacked the aircraft and flown them into the twin towers” if it hadn’t been for the airlines’ negligence, according to a New York court filing.

While WTCP wants $8.4 billion to cover damages, Judge Alvin Hellerstein has limited the amount to the $2.805 billion paid for the leases. In their defense, the airlines say they should not go to trial because WTCP has recovered $4.091 billion from insurance companies. However, Judge Hellerstein has said that at this time he cannot reasonably determine the insurance money covered the damages.